The present invention relates to a semiconductor device, and particularly, relates to a semiconductor device having a gate wiring provided around an element region in which a main current path is formed.
In recent years, use of power MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors) has been rapidly increasing for switched mode power supplies having high breakdown voltage for high current, and for energy saving switches for mobile communications equipment including laptop personal computers. In such devices, the power MOSFETs are used in power management circuits, safety circuits in lithium ion batteries, and the like. For power MOSFETS used in such applications, low voltage drive and low on resistance are demanded, so that the power MOSFETs are used with the voltage of a cell. At the same time, high resistance against breakdown from electrostatic charge applied during assembling is also demanded. A trench gate type structure is known as an example of the power MOSFETs (see, for example, Japanese Patent Application Publication NO. 2007-115888).